The present invention relates to cushion backed carpet and more particularly to carpet having a polymer backing preferably formed from a polyurethane-forming composition which is mated to a primary carpet fabric in an in-situ manner without pre-curing the polyurethane-forming composition. A process and apparatus for forming the cushion backed carpet of the present invention are also provided.
Carpet and carpet tiles having cushioned backings are well known to those of skill in the art. Such cushioned backed carpet is disclosed, for example in my U.S. Pat. No. 4,522,857 (incorporated by reference). An example of a prior art tufted carpet product is illustrated in FIG. 1A and an example of a prior art bonded carpet product is illustrated in FIG. 1B herein.
In the prior art tufted carpet, a primary carpet fabric 12 is embedded in an adhesive layer 16 in which is embedded a layer of glass scrim or nonwoven material. A foam base composite 19 is likewise adhesively bonded to the adhesive layer 16. In the prior art tufted carpet illustrated in FIG. 1A, the primary carpet fabric 12 includes a loop pile layer 20 tufted through a primary backing 22 by a conventional tufting process and held in place by a precoat backing layer of latex 24 or other appropriate adhesive including a hot melt adhesive or the like. The foam base composite 19 of the prior art tufted carpet product preferably includes an intermediate layer 26 molded to a layer of urethane foam 28 as illustrated.
The bonded carpet product (FIG. 1B) formed according to the prior art employs the same type of foam base composite 19 adhesively bonded by adhesive laminate layers 16. However, the primary carpet fabric 12 has somewhat different components from that of the tufted product in that it preferably comprises cut pile yarns 34 implanted in a PVC, latex, or hot melt adhesive 36 having a woven or nonwoven reinforcement or substrate layer 38 of fiberglass, nylon, polypropylene or polyester.
The practice utilized in forming the product disclosed in my ""857 patent and other known products involves preforming and curing the foam base composite 19 of urethane foam and backing material by practices such as are disclosed in U.S. Pat. Nos. 4,171,395, 4,132,817 and 4,512,831, to Tillotson (all incorporated by reference). In the present practice, only after this foam base composite is formed and cured to some degree as a modular component, is it laminated to the carpet base.
As will be appreciated, the cost associated with such modular formation and assembly practices may be reduced by a simplified operation in which a primary carpet fabric, either with or without a stabilizing layer of scrim or the like, is laid directly into a polyurethane-forming composition and thereafter curing the polyurethane. The process can be made even more efficient if the polyurethane-forming composition requires no pre-curing prior to joining the carpet base.
Prior to the present invention, the known processes directed to the application of the polyurethane cushioned backings to fabric substrates have relied on the extremely close control of temperature in both the polyurethane composition and the adjoined fabric layer to effect stability through pre-cure of the polyurethane prior to lamination of the primary carpet to form a composite structure. Such pre-cure has been largely considered necessary in order to yield a stable foam structure to which the primary carpet backing could be applied. The application of heat to the polyurethane composition prior to joinder of the heated fabric backing causes polymer cross linking which has heretofore been thought to be necessary to stabilize the foam mixture to a sufficient degree to prevent the collapse of the foam.
The present invention also provides a particularly simple composite structure amendable to in-situ formation of a stable cushion carpet composite which is not believed to have been previously utilized. Specifically, it has not been previously recognized that a single process could be used to bring all the layers of the cushioned carpet composite together by laying a primary carpet fabric, either with or without some degree of preheat, directly into a mechanically frothed polyurethane-forming composition prior to curing the polyurethane and without an intermediate layer of material.
As indicated, the prior art carpet forming processes typically require the separate formation of a foam base composite comprising a backing layer and a layer of urethane foam. The backing layer is then used as an intermediate layer to which a primary carpet fabric and reinforcing layer can be adhesively bonded.
In the potentially preferred practice of the present invention, the base of the primary carpet fabric is adhesively bonded to a layer of non-woven glass reinforcement material to form a preliminary composite. A puddle of polyurethane-forming composition is simultaneously deposited across a nonwoven backing material. The preliminary composite and the polyurethane-forming composition are thereafter almost immediately brought together with the preliminary composite being laid into, and supported by, the polyurethane-forming puddle. The entire structure is then heated to cure the polyurethane forming composition. The preliminary composite may be slightly heated to about 120xc2x0 F. to improve heating efficiency although the process may likewise be carried out without such preheating.
It is to be understood that, as with the prior art products, wherein the primary carpet fabric 12 may have different embodiments, the component structure of the primary carpet fabric is not critical to the present invention. Rather it is intended that any primary carpet fabric having a pile-forming portion and a primary base may be utilized as the primary carpet fabric. By xe2x80x9cprimary basexe2x80x9d is meant any single layer or composite structure including, inter alia, the commonly used layered composite of primary backing 22 and latex precoat 24 previously described in relation to the prior art tufted product (FIG. 1A) and the adhesive layer 36 with reinforcement substrate 38 previously described in relation to the prior art bonded product (FIG. 1B). As will be appreciated, the use of polyester in the primary base structure may be desirable due to the eventual heat curing such structure may undergo. Other embodiments as may occur to those of skill in the art may, of course, also be utilized. For example, in the bonded product, the pile forming yarns could be heat tacked to the substrate 38 as disclosed in my copending Application No. 08/091,309 now U.S. Pat. No. 5,443,881 to permit simplified construction of a primary carpet.
In view of the foregoing it is a general object of the present invention to provide a carpet including a foam cushioned backing formed in-situ.
In that respect, it is an object of the present invention to provide a cushioned carpet composite wherein a reinforcement layer is disposed, at least partially, within a polymer mass which is adjacent a primary carpet with such primary carpet being laid in-situ into a puddle of the polymer without a pre-curing operation.
It is a related object of the present invention to provide a cushioned carpet composite wherein a primary carpet fabric is joined to a reinforcement layer and laid in-situ into a polyurethane-forming composition which has not undergone a pre-cure operation.
It is a further related object of the present invention to provide a continuous process for the in-situ formation of a cushioned carpet composite wherein a reinforcement layer is adhered to the base of a primary carpet fabric simultaneously with the application of a polyurethane-forming composition to a nonwoven backing layer and the primary carpet fabric with the adhered reinforcement layer is laid into the polyurethane-forming composition prior to curing the polyurethane-forming composition to form the carpet composite.
It is still a further related object of the present invention to provide a continuous process for the in-situ formation of a cushioned carpet composite wherein a reinforcement layer is adhered between a primary carpet base and a backing layer through the in-situ application of a polyurethane forming composition without the need for an intermediate adhesion step.
It is still a further related object of the present invention to provide an apparatus for carrying out the continuous in-situ formation of a cushioned carpet composite.
Accordingly, it is a feature of the present invention to provide a cushioned carpet composite including a primary carpet fabric in laminar relation to a reinforcement layer wherein such reinforcement layer is at least partially embedded in a polyurethane foam layer which is disposed adjacent to a nonwoven backing layer. The reinforcement layer may be bonded to the base of the primary carpet fabric by the polyurethane foam or by a separate adhesive.
It is a further feature of the present invention to provide a process for forming a cushioned carpet composite including the simultaneous continuous steps of adhering a woven or non-woven reinforcement material to the base of a primary carpet fabric; depositing a puddle of a polyurethane-forming composition across a backing layer or support structure and laying the primary carpet fabric and adhered reinforcement material into the puddle of polyurethane-forming composition deposited on the backing layer.
It is a subsidiary feature of the present invention to provide a single step process for forming a cushioned carpet composite including applying a polyurethane-forming composition adjacent a primary carpet fabric and a nonwoven backing layer with the polyurethane-forming composition at least partially holding an intermediate layer of reinforcement material.
It is yet a further feature of the present invention to provide an apparatus for use in the continuous in-situ formation of a cushioned carpet composite wherein the apparatus includes a polymer application unit for depositing a polyurethane-forming composition or other suitable polymer in combination with an adhesive application apparatus for adhering a reinforcement layer to the base of a primary carpet fabric. The polymer application unit and the adhesive application unit being simultaneously operable in controlled relation to one another such that the primary carpet with the adhered reinforcement layer may be laid directly into the polymer.
In accordance with one aspect of the present invention, a cushioned carpet is provided. The cushioned carpet comprises a primary carpet having a primary base and a plurality of pile-forming yarns projecting outwardly from one side. A layer of reinforcement material is bonded to the primary base on the side away from the pile-forming yarns. The reinforcement material is adjacent to, and embedded at least partially in, a cushion layer of polymer such as polyurethane. There is preferably no additional adhesive between the cushion layer and the layer of reinforcement material. An optional backing material is preferably disposed on the underside of the cushion layer. The backing material may include an adhesive backing on the side away from the cushion layer.
In accordance with another aspect of the present invention, a process for making a cushioned carpet is provided. The process involves obtaining a primary carpet fabric comprising a plurality of pile-forming yarns extending outwardly from one side of a primary base. A layer of reinforcement material is adhered to the primary carpet fabric on the side from which the pile-forming yarns do not extend, thereby forming a preliminary composite. A puddle of polymer such as a polyurethane-forming composition is applied to one side of a backing material and preferably doctored to desired thickness. The preliminary composite is then laid into the puddle of polymer without curing. Following this mating operation the polymer is preferably heat cured and the carpet is cut into tiles.
In accordance with still another aspect of the present invention, an apparatus for use in forming a cushioned carpet composite is provided, comprising: a reinforcement bonding unit for bonding a layer of reinforcement material to the underside of a primary carpet fabric to form a preliminary carpet composite; a polymer application unit for dispersing a polyurethane-forming composition across the surface of a carrier fabric; a mating unit for laying said preliminary carpet composite into said polyurethane-forming composition; and means for heat curing the polyurethane-forming composition subsequent to said preliminary composite being laid into said polyurethane-forming composition; wherein said reinforcement bonding unit, said polymer application and said mating unit are operable in a continuous, simultaneous manner.